Here is my theory on what's gonna happen and what has happened.
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neville is the chosen one
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Dumbledore knows and has been protecting neville by allowing LV to believe that is his mortal enemy
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neville knows as he pleads with Harry not to hand over the prophesy.
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Dumbledore was at the Potters death and gave Harry his scar to both protect Harry and fool LV that Harry has been marked as per prophesy.
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re gleam in Dumbledores eye theory in Gob. This is because Dumbledore realises that LV has failed to make himself immortal because he has taken the blood from the wrong boy.
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this tale will end with Neville killing LV (note-Nevilles increasing powers). Dumbledore reveals all to Harry of how he, Lily and James protected Neville by keeping LV's focos on the stronger boy.
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sorry if I ruined it for you, I ruined it for myself
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